(CNSNews.com) – Deepening concern about the possibly imminent execution of an Iranian pastor sentenced to death for “apostasy” prompted both the White House and State Department to issue strongly-worded statements Thursday.

Youcef Nadarkhani’s fate has been in the balance for many months, as his case moved between a court in his home province, Iran’s Supreme Court, and the office of supreme leader Ayatollah Ali Khamenei.

Recent days brought reports that judicial authorities had reissued an execution order, prompting fears that Nadarkhani could be hanged without notice at any time – in line with Iranian practice.

White House press secretary Jay Carney in a statement called the situation “yet another shocking breach of Iran’s international obligations, its own constitution, and stated religious values.”

“The United States stands in solidarity with Pastor Nadarkhani, his family, and all those who seek to practice their religion without fear of persecution – a fundamental and universal human right,” he said.

“The United States calls upon the Iranian authorities to immediately lift the sentence, release Pastor Nadarkhani, and demonstrate a commitment to basic, universal human rights, including freedom of religion.”

Carney said the U.S. again urged governments and people of conscience around the world to press Tehran to release Nadarkhani.

The call was echoed by State Department spokesman Mark Toner.

“Such government persecution for simply following one’s faith is common in Iran, where followers of many religious traditions face harsh treatment and severe violations of their religious freedom,” he said. “We have also witnessed a dramatic increase in the arrest of adherents to the Baha’i faith recently, as well as an increase in repression of freedom of expression in all forms.”

The State Department first expressed concern about Nadarkhani last July.

The American Center for Law and Justice (ACLJ), which has been deeply involved in the case, welcomed the new statements.

“We greatly appreciate the White House’s and State Department's efforts on behalf of Pastor Youcef and join in urging other nations of the world to intervene with the Iranian regime on his behalf,” said executive director Jordan Sekulow. “It is absolutely critical that we continue to place international pressure on Iran for Pastor Youcef’s immediate and unconditional release.”

Nadarkhani was arrested in October 2009, more than a decade after embracing Christianity at the age of 19. Accused of apostasy and evangelizing Muslims he was put on trial in his home province of Gilan, convicted in late 2010 and sentenced to death.

He appealed, and the Supreme Court ruled last July that the lower court must reexamine whether Nadarkhani was a practicing Muslim at the time he became a Christian. If he was and if he failed to “repent,” the court ruled, the execution must go ahead.

Over the following months Nadarkhani – who is married and has two sons under 10 – was asked repeatedly to renounce his faith on pain of death, but refused. In October the case was referred to Khamenei.

This week the ACLJ and other organizations involved in his case learned that an execution order had reportedly been issued.

“There are grave concerns that the death sentence could be carried out at any time without prior notification and that the authorities will merely announce it later, a practice that is not uncommon in Iran,” Christian Solidarity Worldwide said in a statement.

Jason DeMars of Present Truth Ministries, who has sources close to the case, voiced the same concern.

“Based upon how the Iranian courts have acted in the past we do not know what to anticipate,” he said. “Often they will execute people without any prior notice to attorneys or family. The [execution] order has not been delivered to Youcef’s family and we do not know if they will allow another appeal. We also do not know if it has been approved by the Ayatollah who is the head of the judiciary, Sadegh Larijani.

“At this point I ask that you be praying for his deliverance and that God would use this as an opportunity to declare to everyone that all power is given to the Lord Jesus Christ and resides in His Name,” DeMars said. “It is never too late for the Lord to bring deliverance.”

According to Amnesty International and Human Rights Watch, Iran executed more than 600 people last year. Only China carries out more executions.

On Feb. 17, a resolution was introduced in the House of Representatives calling on Iran “to exonerate and immediately release Youcef Nadarkhani and all other individuals held or charged on account of their religion.”

An ACLJ petition urging all members of Congress to support the resolution had drawn more than 106,000 signatures by early Friday.

ACLJ also is inviting people with Twitter accounts to sign up for a feature that enables the organization to send out one Twitter message a day updating the situation. It says the messages are already reaching more than 600,000 Twitter accounts, in 85 percent of the world's countries.